In this paper, a slotted conical patch connected to a small triangular patch multiband antenna for both microwave and millimeter-wave applications is presented. The designed antenna has three characteristics. The proposed antenna is a multiband, having a compact size of 0.35λ0 × 0.35λ0 × 0.004λ0 at its lowest operational frequency, i.e., 2.4 GHz, and more importantly, it can cover both the microwave and millimeter-wave bands with a single feeding. According to the −10 dB matching bandwidth, experimental results show that the antenna operates at (2.450–2.495) GHz, (5.0–6.3) GHz, and (23–28) GHz. The reduced size, simple design, and multiband large bandwidth are some of the advantages over the reported designs in the latest literature. Both simulated and experimental results show a good agreement, and the proposed antenna can be used for wireless local area network (WLAN) applications and fifth-generation (5G) wireless communication devices.
In this paper, we propose a periodic structure that is capable of alternating between absorption and radiation mode. The designed periodic structure consists of an array of 6×6 square shaped unit cell. Each unit cell consists of a multi-layered structure, with dimensions of 0.5λ×0.5λ. The resonators are placed on the top layer and the feeding network is designed and implemented on the bottom layer. The ground layer is sandwiched between the two dielectric substrates. All resonators are connected to a 50 feed-line using the corporate feeding technique. To achieve broadband absorption, lumped resistors are inserted into the resonators. The proposed metasurface structure achieves broadband radiation, with low RCS and high gain, in the propagation direction whereas broadband absorption is achieved, when it is exposed to a free space plane wave. Moreover, the metamaterial absorber has stable absorptivity for an incident angle of (0 •-30 •). To verify the in-band absorption and radiation of the proposed design, a 6×6 periodic array of resonators has been fabricated and experimentally verified in an anechoic chamber. The measured results validate the performed simulations.
Blind source separation (BSS) is a problem that appears in many research fields. Fast Independent components analysis (FastICA) is one of the techniques to solve the problem. The researchers have verified the effectiveness of the technique through the offline analysis of the public datasets. The development of a real-time portable system involving such a computationally complex analysis requires an efficient hardware implementation of FastICA. A Field programmable gate array (FPGA) and an applicationspecific integrated circuit (ASIC) are two promising hardware platforms to implement FastICA. This work proposes a new method, called ALgebraic Jacobi Method (ALJM), for performing eigenvalue decomposition (EVD) required for the implementation of FastICA. We use a simplification, a polynomial approximation, and the Newton-Raphson method for calculating the Jacobi rotation. In this way, we ensure hardware reusability between the EVD stage and the weight vector estimation (WVE) stage of FastICA which reduces the computational complexity and the power consumption, without compromising its computation speed. We evaluate the ALJM-based FastICA by performing BSS on the linear mixtures of the deterministic and the random signals and comparing the performance results with the existing methods. After verifying its functionality and numerical stability, we propose a scalable systolic processing array (SPA) for the ALJMbased FastICA and implement it on Spartan-6 FPGA. By comparing the existing implementations of FastICA, in terms of speed, area, and power, we conclude that the ALJM-based FastICA is one of the most efficient methods for prototyping and commercializing a real-time portable system comprising FastICA.
The authors have proposed an Ultrabroadband Metamaterial Microwave Absorber. The authors have claimed that the proposed structure is metamaterial absorber. We have recognized that the designed structure is not a metamaterial absorber because of ignorance of cross-polarized reflection coefficient. The designed structure is polarization convertor because the proposed unit cell has an-isotropic geometry.
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